In the Fourth National Report on Human Exposure to Environmental Chemicals (Fourth Report), CDC scientists measured cadmium in the blood of 8,372 participants aged one year and older and in the urine of 2543 participants aged six years and older who took part in the National Health and Nutrition Examination Survey (NHANES) during 2003–2004. Prior survey periods of 1999–2000 and 2001–2002 are also included in the Fourth Report. By measuring cadmium in blood and urine, scientists can estimate the amounts of cadmium that have entered people's bodies.
CDC researchers found cadmium in most participants. Blood and urinary cadmium levels are known to increase with age, as seen in the Fourth Report.
The highest levels of urine cadmium in the U.S. population were only slightly lower than levels associated with indicators of changes in the kidney.
Finding a measurable amount of cadmium in blood or urine does not imply that the levels of cadmium cause an adverse health effect. Biomonitoring studies on levels of cadmium provide physicians and public health officials with reference values so that they can determine whether people have been exposed to higher levels of cadmium than are found in the general population. Biomonitoring data can also help scientists plan and conduct research on exposure and health effects.